The present invention is directed to manufacture of glassware such as hollow glass containers, and more particularly to a communication system for implementing automatic control of one or more aspects of a glassware forming system.
The science of glass container manufacture is currently served by the so-called individual section machine. Such machines comprise a plurality of separate or individual manufacturing sections, each of which includes a multiplicity of operating mechanisms for converting hot gobs or charges of molten glass into hollow glass containers. In general, each section includes one or more blank molds in which a glass gob is initially formed in a blowing or pressing operation, an invert arm for transferring each blank or parison to a blow mold in which the container is blown to final form, tongs for removing the containers onto a deadplate, and a sweep-out mechanism for sweeping the containers from the deadplate onto a conveyor. Additional mechanisms in the machine provide for closure of mold halves, movement of baffles and blow nozzles, control of mold cooling wind, etc. Other controllable mechanisms control operation of the conveyor, inspection of containers passing along the conveyor, transfer of the containers to an annealing lehr, etc. U.S. Pat. Nos. 4,762,544, 5,580,366 and 5,624,473 illustrate systems of this character.
It is a general object of the present invention to provide a network for interconnecting the operating devices of a glassware manufacturing system for bidirectional communication employing a CANbus communication protocol, in which the length of the interconnection cables need not be identical, which exhibits reduced noise susceptibility, and in which an operating device may be disconnected from the communication network for replacement or repair without interrupting communications among the remaining devices.
A glassware forming system in accordance with one aspect of the present invention includes a plurality of electronic devices for performing operations on articles of glassware. These devices may comprise devices for controlling the glassware forming operation by controlling one or more operating mechanisms of a glassware forming system, or may comprise devices for inspecting articles of glassware for commercial variations that may affect commercial acceptability of the glassware and call for possible adjustment or repair of the glassware forming system. A network interconnects the devices for intercommunication among the devices, and includes a star network hub and conductors connecting the hub to the plurality of devices in a star network configuration for bidirectional communication among the devices through the hub. The star network hub includes a hub controller for controlling operation of the hub according to a CANbus communication protocol, circuitry for sensing initiation of communication from one of the devices, and circuitry for blocking transmission of such communication to the device from which the communication is initiated and enabling communication from the device through the star network hub to all other devices connected to the hub. The star network hub preferably also includes circuitry responsive to termination of communication from the one device for delaying enablement of communication from other devices to accommodate differences in length of the interconnection conductors or fiberoptics.